Autoindent inconsistencies

[GHGibonus]

While editing a fork of elm-vim, I noticed some unexpected behaviors in the way autoindent works. Notably I found two issues.

1. else clauses in if expressions do not align with the parent if:
   When I write an if else expression, I expect autoindent to align the else with a parent if, like so:

   fun : Int -> Bool
   fun x =
       if x == 0 then
           False
       else
           True

   Instead, when I type else, else do not align itself with the parent if. I get the following:

   fun : Int -> Bool
   fun x =
       if x == 0 then
           False
           else
               True

   Note that the former is the way let in expressions work and it is reasonable to assume that if else expressions would work the same way.
   This is a non-issue when using a snippet insertion plugin such as UltiSnip. However, having the base indent plugin work is a nice goal to have.

2. Operators starting a new line do not in indent.
   When using the pipe operator especially, one expects that the line is indented such as:

   fun : List a -> List a
   fun l =
       tail l
           |> reverse
           |> drop 5

   However, what I get is the following:

   fun : List a -> List a
   fun l =
       tail l
       |> reverse
       |> drop 5

Looking at the indent/elm.vim file, I found that those behaviors were intended, but the implementation just do not work.